Hydraulic lash adjusters (also sometimes referred to as “lifters”) for internal combustion engines have been in use for many years to eliminate clearance (or “lash”) between engine valve train components under varying operating conditions, in order to maintain efficiency and to reduce noise and wear in the valve train. Hydraulic lash adjuster operate on the principle of transmitting the energy of the valve actuating cam through hydraulic fluid trapped in a pressure chamber under a plunger. In a Type II valve train, the plunger is known as a “ball plunger” because it has a ball-shaped portion at one end and a seat surface at its other end. During each operation of the cam, as the length of the valve actuating components varies as a result of temperature changes and wear, small quantities of hydraulic fluid are permitted to enter the pressure chamber, or escape therefrom, thus effecting an adjustment in the position of the ball plunger, and consequently adjusting the effective total length of the valve train.
As is known in the art, ball plungers have been initially made in cold-forming machines and then machined to achieve a desired final shape. However, machining processes are time consuming and add to the cost of the finished ball plunger. There are continual efforts to improve upon the processes to manufacture ball plungers, particularly to reduce the machining time and costs associated therewith.